Pistons for internal combustion engines have become increasingly complexed due to many factors including size, heat, and materials. As the piston tends to heat up, it tends to expand non-uniformly due to the difference in thickness of the metal in different parts of the piston. In order to get a proper seating in the cylinder for maintaining maximum compression, it is necessary to conform the piston so that when it is in its heated and operating state, it more nearly forms a perfect cylinder.
Typical of a machine for doing this type of work is that of De Biasse, U.S. Ser. No. 803,685 filed June 6, 1977 owned by the assignee of this application and such patented developments as Allan, U.S. Pat. No. 3,373,640 of Mar. 19, 1968 and Dall, U.S. Pat. No. 2,735,420 of Feb. 21, 1956. The invention disclosed in these items provide a rotating circumferential cam mounted on the spindle and some type of axial cam profiling means in some way connected therewith for providing a movement of the tool so that it will cut or machine a complex contour on the work both axially and radially.
Where very complexed profiles are required, it has been necessary in the past to perform the cutting operation in a series of stages rather than by a single continuous cut. Further, there has generally been a complex cam linkage between the circumferential cam on the spindle and the axial cam generally mounted parallel to the axis of the spindle. The longer the linkage the more problems in maintaining extreme accuracy as required in many pistons today.